Malleability can be defined as the ability of a distributed parallel job to change the number of processes without pausing its execution by reallocating the computational resources originally assigned to the job. The aim of this paper is to introduce MaM, a library that allows to incorporate malleability into parallel MPI-based applications using different methods and strategies. Its API enables the application developer to use MaM’s capabilities in an easy and nearly transparent way. The paper also analyzes the cost of reconfigurations using the methods and strategies offered by MaM.